This invention relates to mandrels on which hollow shells or casings are formed.
Mandrels are frequently used to form relatively thin casings for fuel in missiles. The casings are generally formed by winding a filamentary material impregnated with a plastic resin onto the mandrel.
The mandrels are generally hollow and are usually fabricated from a frangible plaster-like material which must be strong, lightweight and capable of maintaining an extremely accurate outer surface as the filaments are wound thereon under tension. After the casing has been wound and cured, the mandrel must be broken up and removed through the ports normally provided in at least one end of the case. Removal of the mandrel must be done without damaging or distorting the relatively thin casing. Since the mandrel must have a solid wall of substantial thickness and density in order to have adequate strength during the winding operation, the subsequent breaking up of the mandrel requires painstakingly careful chiseling to break the mandrel into pieces of a size which can be removed through a porthole, and at the same time not damage or in any way detract from the contour accuracy of the outer shell.
It is an object of this invention to provide an improved hollow mandrel.
Other objects and advantages of the present invention will be apparent to those skilled in the art from a consideration of the following disclosure.